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Data not stored into realm database

java.lang.IllegalStateException: Your Realm is opened from a thread
without a Looper and you provided a callback, we need a Handler to
invoke your callback
I'm Writing a code that will do in background- read from a text file(inside assets) and then placing them into a realm database.But i seem to get this error
"java.lang.IllegalStateException: Your Realm is opened from a thread without a Looper and you provided a callback, we need a Handler to invoke your
callback"
In my onCreate i have this
Realm.init(context);
realm = Realm.getDefaultInstance();
ParseInBackground task = new ParseInBackground();
task.execute();
and in the do-in-background task of AsyncTask i got this
try {
realm = Realm.getDefaultInstance();
realm.executeTransactionAsync(new Realm.Transaction() {
#Override
public void execute(Realm bgRealm) {
final ModelClass modelClass = bgRealm.createObject(ModelClass.class);
try {
InputStream file = getAssets().open("goodie.txt");
reader = new BufferedReader(new InputStreamReader(file));
final String[] line = {reader.readLine()};
while (line[0] != null) {
handler.post(new Runnable() {
#Override
public void run() {
try {
line[0] = reader.readLine();
} catch (IOException e) {
e.printStackTrace();
}
String[] namelist = line[0].split(":");
String iWord = namelist[0];
String iDesc = namelist[1];
modelClass.setName(iWord);
modelClass.setDesc(iDesc);
count++;
}
});
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (realm != null)
realm.close();
}
}
}, new Realm.Transaction.OnSuccess() {
#Override
public void onSuccess() {
Toast.makeText(MainActivity.this, "Added " + count + "items", Toast.LENGTH_SHORT).show();
}
}, new Realm.Transaction.OnError() {
#Override
public void onError(Throwable error) {
}
}
);
} catch (Exception e) {
e.printStackTrace();
}
and a Model class called ModelClass has this
private String name;
private String desc;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
Desperately in need of help.Thanks in advance

Check http://developer.android.com/reference/android/os/Handler.html and http://developer.android.com/reference/android/os/Looper.html
Basically Realm need a way to communicate with your thread when doing asyc query, on Android, naturally Looper and Handler is the way to go.
Check this for more sample code.
https://github.com/realm/realm-java/tree/master/examples/threadExample

You need to remove Handler.post(...) from within the execute callback.
realm.executeTransactionAsync(new Realm.Transaction() {
#Override
public void execute(Realm bgRealm) {
final ModelClass modelClass = bgRealm.createObject(ModelClass.class);
try {
InputStream file = getAssets().open("goodie.txt");
reader = new BufferedReader(new InputStreamReader(file));
final String[] line = {reader.readLine()};
while (line[0] != null) {
try {
line[0] = reader.readLine();
} catch (IOException e) {
e.printStackTrace();
}
String[] namelist = line[0].split(":");
String iWord = namelist[0];
String iDesc = namelist[1];
modelClass.setName(iWord);
modelClass.setDesc(iDesc);
count++;
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (realm != null)
realm.close();
}
}
}, new Realm.Transaction.OnSuccess() {
#Override
public void onSuccess() {
Toast.makeText(MainActivity.this, "Added " + count + "items", Toast.LENGTH_SHORT).show();
}
}, new Realm.Transaction.OnError() {
#Override
public void onError(Throwable error) {
}
}
);
} catch (Exception e) {
e.printStackTrace();
}
I hope this helps.

How to make a program wait for a method in java

I am writing a programm that returns me a ArrayList of Strings. Problem is, when I call the method the list is not filled yet so I get an empty list back .
I tried it with a thread but now I get a null reference when I call the method. By the way i had to implement a async task, otherwise I get an exception when trying to use InetAddress.
private class DeviceManager extends Thread {
private ArrayList<String> deviceList;
private String networkIP;
public DeviceManager(String networkIP) {
this.networkIP = networkIP;
}
public void run() {
getDeviceList();
}
public ArrayList<String> getDeviceList() {
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
deviceList = new ArrayList<String>();
InetAddress address;
Log.i("NetworkIPgetDeviceList", networkIP);
String deviceIP = networkIP;
for (int i = 0; i < 255; i++) {
address = InetAddress.getByName(deviceIP += "" + i);
if (address.isReachable(2000)) {
Log.i("Devicefound", deviceIP);
deviceList.add(deviceIP);
}
deviceIP = networkIP;
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}.execute();
return deviceList;
}
public ArrayList<String> getList() {
return this.deviceList;
}
}

Artur what you are doing in your code is starting a thread to retrieve device list and then another thread(AsyncTask) to actually creates the device list. So you have three threads running here simultaneously (assuming you are using DeviceManager class in UIThread). The reason getDeviceList() is returning null is because AsyncTasks doInBackground hasn't run yet to collect your device list it might be waiting for its chance to get scheduled. so to conclude that, you just need one thread(other than UIThread), it can either be a Thread or AsyncTask (more preferable as it gives better control) as rusted brain has used in his answer. I prefer to make DeviceManager as AsyncTask (just a bit cleaner and if device managers only task is to retrieve device list) as code below.
in AsyncTask doInBackground runs in a background thread(as name suggests) and onPostExecute runs on the UI thread after doInBackground
class DeviceManager extends AsyncTask<String, Void, List<String>> {
private ConnectionCompleteListener listener;
public interface ConnectionCompleteListener {
void onSuccess(List<String> deviceList);
// if you need to know reason for failure you can add
// parameter to onFailure
void onFailure();
}
public DeviceManager(ConnectionCompleteListener listener) {
this.listener = listener;
}
#Override
protected List<String> doInBackground(String... params) {
List<String> deviceList = new ArrayList<>();
String networkIP = params[0];
try {
InetAddress address;
Log.i("NetworkIPgetDeviceList", networkIP);
String deviceIP = networkIP;
for (int i = 0; i < 255; i++) {
address = InetAddress.getByName(deviceIP += "" + i);
if (address.isReachable(2000)) {
Log.i("Devicefound", deviceIP);
deviceList.add(deviceIP);
}
deviceIP = networkIP;
}
} catch (IOException e) {
deviceList = null;
e.printStackTrace();
}
return deviceList;
}
#Override
protected void onPostExecute(List<String> deviceList) {
if (deviceList == null) {
this.listener.onFailure();
} else {
this.listener.onSuccess(deviceList);
}
}
}
so in your activity you can call
new DeviceManager(new DeviceManager.ConnectionCompleteListener
() {
#Override
public void onSuccess(List<String> deviceList) {
}
#Override
public void onFailure() {
}
}).execute("YOUR_NETWORK_IP");

You are doing it completely wrong. A Thread runs in the background and so does AsyncTask, so basically you are making a background task run in background. Inception.
Try this:
public class DeviceManager {
private ArrayList<String> deviceList;
private String networkIP;
private ConnectionCompleteListener listener;
public interface ConnectionCompleteListener {
void onSuccess();
void onFailure();
}
public void setConnectionCompleteListener(ConnectionCompleteListener listener) {
this.listener = listener;
}
public DeviceManager(String networkIP) {
this.networkIP = networkIP;
}
public void getDeviceList() {
new AsyncTask<Void, Void, Boolean>() {
#Override
protected void onPostExecute(Boolean result) {
if(result) listener.onSuccess();
else listener.onFailure();
}
#Override
protected Boolean doInBackground(Void... params) {
try {
deviceList = new ArrayList<String>();
InetAddress address;
Log.i("NetworkIPgetDeviceList", networkIP);
String deviceIP = networkIP;
for (int i = 0; i < 255; i++) {
address = InetAddress.getByName(deviceIP += "" + i);
if (address.isReachable(2000)) {
Log.i("Devicefound", deviceIP);
deviceList.add(deviceIP);
}
deviceIP = networkIP;
}
return true;
} catch (UnknownHostException e) {
e.printStackTrace();
return false;
} catch (IOException e) {
e.printStackTrace();
return false;
}
return null;
}
}.execute();
}
public ArrayList<String> getList() {
return this.deviceList;
}
}
Then in your other class:
private class classname{
DeviceManager manager=new DeviceMnager(networkIp);
manger.setConnectionCompleteListener(new DeviceManager.ConnectionCompleteListener() {
#Override
public void onSuccess() {
// get your list here
manager.getList();
}
#Override
public void onFailure() {
// connection failed show error
}
});
}

You are getting empty array list because as you are using async task for getting array list and async task doINBackground method runs on different thread(means not on main thread). So when your program runs then your program doesn't wait for async task response.
You can solve this like that...
Use onPostExecute method in async task class and return the arraylist
#Override
protected void onPostExecute(Void result) {
//return array list here
getList();
}
Hope this will help you

First of All you don't need to make DeviceManager a thread as the task which you are running in getDeviceList will start in another new thread. Second You shouldn't wait on main(UI) thread so instead of waiting callback is a better mechanism.
If you insist on the same code try this..
public class DeviceManager extends Thread {
private ArrayList<String> deviceList;
private String networkIP;
private boolean dataAvailable;
public DeviceManager(String networkIP) {
this.networkIP = networkIP;
}
public void run() {
getDeviceList();
}
public ArrayList<String> getDeviceList() {
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
try {
deviceList = new ArrayList<String>();
InetAddress address;
Log.i("NetworkIPgetDeviceList", networkIP);
String deviceIP = networkIP;
for (int i = 0; i < 255; i++) {
System.out.println("checking " + i);
address = InetAddress.getByName(deviceIP += "" + i);
if (address.isReachable(2000)) {
Log.i("Devicefound", deviceIP);
deviceList.add(deviceIP);
}
deviceIP = networkIP;
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
dataAvailable = true;
synchronized (DeviceManager.this) {
DeviceManager.this.notify();
}
return null;
}
}.execute();
return deviceList;
}
synchronized public ArrayList<String> getList() {
while (!dataAvailable) {
try {
wait();
} catch (InterruptedException e) {
}
}
return this.deviceList;
}
}

AsyncTask not calling onPostExecute

Other class:
SpotifyTask st = new SpotifyTask(new Closure<JSONObject>() {
#Override
public void executeOnSuccess(JSONObject result) {
track.setJson(result);
}
});
st.execute("asd");
Being SpotifyTask:
public class SpotifyTask extends AsyncTask<Object, Void, JSONObject> {
private final Closure<JSONObject> closure;
public SpotifyTask(Closure<JSONObject> closure) {
this.closure = closure;
}
public static void getTrack(Closure<JSONObject> closure) {
new SpotifyTask(closure).execute("asd");
}
#Override
protected JSONObject doInBackground(Object... params) {
JSONObject result = null;
SpotifyCall spcall = new SpotifyCall();
try {
result = spcall.getTrack();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return result;
}
#Override
protected void onPostExecute(JSONObject result) {
System.out.println("ASD: on post execute "+result);
closure.executeOnSuccess(result);
}
}
So... doInBackground is running OK, and and returning a JSONObject all right; I know because Im debbuging it and "result" IS a JSONObject.
But onPostExecute is never executed, the debugger never gets there and "ASD: on postexecute "+result is never logged.
Any suggestions?
Thanks in advance!

The problem was that I was "holding" the UI Thread:
this.status = "loading";
final Track track = new Track();
SpotifyTask.getTrack(new Closure<JSONObject>() {
#Override
public void executeOnSuccess(JSONObject result) {
track.setJson(result);
}
});
while (this.status.equals("loading")) {
if (track.getJson() != null) {
this.trackUno = track.getJson();
this.status = "ready";
} else {
try {
System.out.println("Not ready, waiting.");
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
As soon I removed the while block, it worked perfectly.
I would have to find another way to "wait" for the call to be complete.
Thanks for your time fellas!

How to create a boolean method to return value from handler

I have created a class to check access of internet on device, my class code is
public class CheckInternet {
private static Handler h = new Handler() {
#Override
public void handleMessage(Message msg) {
if (msg.what != 1) { // code if not connected
status = false;
System.out.println("Status False");
} else { // code if connected
status = true;
System.out.println("Status True");
}
}
};
private static void isNetworkAvailable(final Handler handler, final int timeout) {
new Thread() {
private boolean responded = false;
#Override
public void run() {
new Thread() {
#Override
public void run() {
HttpGet requestForTest = new HttpGet("http://m.google.com");
try {
new DefaultHttpClient().execute(requestForTest); // can last...
responded = true;
} catch (Exception e) {}
}
}.start();
try {
int waited = 0;
while(!responded && (waited < timeout)) {
sleep(100);
if(!responded ) {
waited += 100;
}
}
}
catch(InterruptedException e) {} // do nothing
finally {
if (!responded) { handler.sendEmptyMessage(0);
}
else { handler.sendEmptyMessage(1);
}
}
}
}.start();
}
}
I want to create a public static boolean method which returns me the status, I have come up with some code
private static Boolean status = true ;
public static Boolean isConnected() {
Runnable runnable = new Runnable() {
public void run() {
// TODO Auto-generated method stub
isNetworkAvailable(h,2000);
}
};
runnable.run();
return status;
}
But the issue is that it always returns me the old status value, as while the time the thread is running, the method send me the old status value.
I want to get the updated status value.

You better use
isReachable(timeout)
http://docs.oracle.com/javase/6/docs/api/java/net/InetAddress.html#isReachable%28java.net.NetworkInterface,%20int,%20int%29
Regards

ANR force close when running this code

This code is causing ANR force close any idea how to improve this code? i try with asynctask and i cant make it work in this code :
What i try to do here is updater activity will check for latest version and if got new version it will pop up alertdialog to ask user to update in the market
public class Updater extends Activity {
private int newVerCode = 0;
private String newVerName = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
if (getServerVerCode()) {
int vercode = Config.getVerCode(this);
if (newVerCode > vercode) {
doNewVersionUpdate();
} else {
notNewVersionShow();
}
}
}
//check version using json
private boolean getServerVerCode() {
try {
String verjson = NetworkTool.getContent(Config.UPDATE_SERVER
+ Config.UPDATE_VERJSON);
JSONArray array = new JSONArray(verjson);
if (array.length() > 0) {
JSONObject obj = array.getJSONObject(0);
try {
newVerCode = Integer.parseInt(obj.getString("verCode"));
newVerName = obj.getString("verName");
} catch (Exception e) {
newVerCode = -1;
newVerName = "";
return false;
}
}
} catch (Exception e) {
return false;
}
return true;
}
//Found No new version
private void notNewVersionShow() {
Updater.this.finish(); // End updater activity
}
//Found New version
private void doNewVersionUpdate() {
//Display alertdialog
}
}

You can use an AsyncTask - yes. In doInBackground you can add the code from getServerVerCode() and in onPostExecute everything in the if (getServerVerCode()).
doInBackground can return boolean so you know in onPostExecute what the result is.
Something like this:
private class GetServerVerCode extends AsyncTask<Void, Void, Boolean> {
#Override
protected Boolean doInBackground(Void... params) {
try {
String verjson = NetworkTool.getContent(Config.UPDATE_SERVER
+ Config.UPDATE_VERJSON);
JSONArray array = new JSONArray(verjson);
if (array.length() > 0) {
JSONObject obj = array.getJSONObject(0);
try {
newVerCode = Integer.parseInt(obj.getString("verCode"));
newVerName = obj.getString("verName");
} catch (Exception e) {
newVerCode = -1;
newVerName = "";
return false;
}
}
} catch (Exception e) {
return false;
}
return true;
}
#Override
protected void onPostExecute(Boolean result) {
if (result) {
int vercode = Config.getVerCode(this);
if (newVerCode > vercode) {
doNewVersionUpdate();
} else {
notNewVersionShow();
}
}
}
}